Question 1: Define absorption in the context of black body radiation.

Answer: Absorption is the process by which materials take in incident electromagnetic radiation, converting it into other forms of energy, such as heat.

Question 2: Explain why dark-coloured sports gear, such as jerseys or equipment, tend to absorb more thermal radiation compared to lighter colours.

Answer: Dark colours have a higher absorption coefficient, meaning they absorb more electromagnetic radiation, which can increase their heat intake.

Question 3: Describe the mechanism by which materials used in sportswear can absorb infrared radiation during outdoor activities.

Answer: Materials with high emissivity absorb infrared radiation effectively, converting it into heat, which can influence the temperature of the sportswear.

Question 1: A sports jacket has an absorption coefficient of 0.85 for infrared radiation. If it is exposed to a thermal radiation intensity of 500 W/m², calculate the power absorbed per square metre of the jacket.

Answer: Power absorbed = Absorption coefficient × Intensity = 0.85 × 500 W/m² = 425 W/m²

Question 2: If a sports helmet made of a material with an absorption coefficient of 0.65 absorbs 260 W of thermal energy, what is the incident radiation intensity? Show your work.

Answer: Intensity = Power absorbed / Absorption coefficient = 260 W / 0.65 ≈ 400 W/m²

Question 1: Outline a simple experimental setup to measure the absorption of infrared radiation by different sports fabrics. Include the key variables to control.

Answer: Use an infrared source, samples of sports fabrics, and an infrared detector. Control variables such as fabric thickness, material type, and radiation intensity. Measure the temperature change or energy absorbed over time.

Question 2: Identify two safety precautions to consider when conducting experiments involving thermal radiation and sports materials.

Answer: Wear heat-resistant gloves to prevent burns and ensure proper ventilation to avoid overheating of equipment.

Question 1: A sports team notices their dark-coloured training shirts become significantly warmer than the light-coloured ones after outdoor practice in the sun. Explain this observation using the concept of absorption.

Answer: Dark-coloured shirts have higher absorption coefficients, so they absorb more solar radiation, leading to higher temperatures compared to light-coloured shirts.

Question 2: During a heat therapy session, a thermal blanket made of a material with high emissivity is used. Describe how absorption and emission properties of the blanket contribute to heat transfer.

Answer: The blanket absorbs infrared radiation from the body and then emits infrared radiation back, helping to retain body heat and transfer thermal energy efficiently.

Question 1: Explain how the absorption properties of materials can influence the design of sportswear for different climates. (6 marks)

Answer: Materials with high absorption properties are better for cold climates as they can absorb and retain heat, keeping athletes warm. Conversely, materials with low absorption coefficients are preferable in hot climates to reflect or transmit heat, preventing overheating. The choice of fabric colour and texture also affects absorption and heat transfer, influencing athlete comfort and safety.

Question 2: Describe a real-world scenario where understanding absorption could improve safety or performance in sports.

Answer: Designing sports gear with materials that absorb or reflect infrared radiation can help regulate body temperature, improving performance and reducing risk of heat-related illnesses during outdoor activities.